The present invention relates to methods for manufacturing electroluminescence devices.
As typical bar-like light emission devices, fluorescent lights or neon tubes are known. The fluorescent lights and the neon tubes emit light through discharge phenomenon of noble gas sealed in a glass tube. However, the light emission devices that emit light through the discharge phenomenon are difficult to reduce in size and consume a relatively great amount of power. To solve these problems, a bar-like electroluminescence device (hereinafter, referred to simply as an “EL device”) having an electroluminescence element (hereinafter, referred to simply as an “EL element”) is focused on as a bar-like light emission device that is smaller and decreases power consumption. The EL element is provided on an outer circumferential surface of a bar-like member.
To manufacture the EL device, a wrapping method and a vapor deposition method are known (see, for example, Japanese Laid-Open Patent Publications Nos. 11-265785 and 2005-108643, respectively). In the wrapping method, a first electrode (an anode), an organic layer, and a second electrode (a cathode) are sequentially arranged on a flexible sheet substrate in this order. The sheet substrate is then wound around a support bar. In the vapor deposition method, an organic layer, an anode, and a seal layer are sequentially vapor-deposited on a bar-like cathode in this order.
However, in the wrapping method of Japanese Laid-Open Patent Publication No. 11-265785, the EL element formed on the sheet substrate must be bent when the sheet substrate is wound around the outer circumferential surface of the support bar. If the support bar becomes smaller, excessive compression stress or excessive extension stress acts on each of the layers that form the EL element, which is wound around the support bar. This may deteriorate the electric characteristics of each layer and decrease productivity for manufacturing the EL device.
In the vapor deposition method of Japanese Laid-Open Patent Publication No. 2005-108643, the layers are provided sequentially through deposition with increased directivity. Thus, if a relatively large EL device or a complicatedly configured EL device must be manufactured, formation of an organic layer or a cathode with uniform thickness becomes difficult. This significantly lowers the productivity for manufacturing the EL device.